Hello everyone, I just wanted to verify something.
I have a 2002 Mitsubishi Diamante AT and when I shift to drive the shift indicator blinks from "Drive to Neutral", it seems like the transmission is stuck in 3rd gear because the take off from a stop is very slow although once over 40 mph it has great power.

I contacted the dealers parts department and I am not sure if they are feeding me BS or not but they claim they need the # off of the old "AT control relay" I asked them where it was and they claim they don't know, I asked them for a cut sheet of the transmission and they said they don't have one, I asked to speak with one of the technicians and they claim that the technicians don't answer phone calls. So then I ask them "well when can I bring my car in for service?" and they are swift to want to schedule me so then I hung up.

Anyhow I came across this forum and was happy to see someone posted some kind of information on this problem.

I used a craftsman OBD2 tool and it threw up this red flag: P1751 A/T Control Relay Malfunction. I erased the code and started the car (It ran perfect in drive but the service engine light came back on). I turned the car back off and ran the test again and got the same P1751 error.

I live in Hawaii so I am pretty sure the heater is not being used so hopefully the ECU is fine.

Is this a common error or when I replace the relay will it turn into something mechanical?

I have an option to sell the car cheap $1200. and get my money back or spend repair costs and maybe buried in it.

 

i am just new here. it did happen to me too i have a 2001 diamante LS with 120k miles on it and having the same problem. I am trying to replace the transmission relay, it is located under the switch for your heated seat passenger side. take off your cup holder and you can see it from there right side from the ECU. The only problem i have is which is the transmission relay because there are 2 relay with the same number next to each other. i only order 1. anybody can help us which should i replace or should i replace both of them?

 

I actually did this procedure and the vehicle is working flawless now. I also went ahead and took off both heater tubes connected to the fire wall inside the engine compartment and spliced them together with a adapter i got from checkers (no more leaking heater into the ECU worry's).

Here is a step by step of what I did to fix this problem.











Install new one and reverse order.

 

There should only be one relay, the one in the picture is the one you want for AT.
The picture at the bottom where the relay is mounted, behind it is the ECU and it should have a plastic cover over it. If that cover is wet with green radiator fluid I suggest eliminating the heater and splicing the hoses together.

 

So, only 1 transmission relay then? since you take out the ash tray all in the front did you see the one i am talking about. It is also a relay. i took a picture of it with my phone, i take out the cup holder. can you take a look of it? there is another relay behind it with the same number.

https://mitsubishiforum.com/forum/at...-wp_000351-jpg

 

The image is small and i don't know how to edit it to make it bigger but see that's a relay and there are 2 of them with the same number. I wonder if you notice those when you take out the ash tray under the car stereo.

 

I start looking for it when i read this in the forum.

https://mitsubishiforum.com/forum/mi...l-relay-33475/

It is old post and nobody want to follow up

 

the post you were looking at states this:
1. Airbag module (very bottom of ECM) part MR538276
2. ECM part MR514497
<< 3. Traction control box (just below the radio mounted vertically) part MR502450.>>

Where is the mystery "transmission relay"?

The only transmission relay on the vehicle should be where I stated unless someone relocated it from the manufactures spot.

Remember the Transmission control box and relay are two totally different entity's, for the problems occurring like in this post the case usually is the Relay.

ALSO: Dont hang too much thought on the part numbers, the dealer can get you the correct part if you ask for (Transmission Relay). Mine was a different part number and from what I have seen these part numbers change from time to time.

 

Thanks for the help and i am done with the transmission relay problem now. I have another problem with my car regarding the "TCL OFF" and "Anti Lock" light are now ON and there are times that "TCL OFF" light is blinking. I wonder if you encounter this kind of problem and how you fix it. Somebody say the sensor but i don't know what kind of sensor and where is the sensor.

I got 2001 diamante ls and it have 121k+ miles. I already change the EGR valve, map sensor, recently the A/T relay and rotor, and still i got another problem with the TCL and ANTI LOCK lights.

I need help

 

It is a tricky process, you can probably look up the how-to on utube for a honda which is similar.

Basically: hook up a OBD meter to your vehicle and check the code it should say "sensor", if it says "ABS" its more likely a bigger problem such as the ABS brain. you can test it by turning the vehicle ignition key "on" and listening for a buzzing noise near the passenger side kick panel, it should be about 15-25 seconds then turn off.


The only way I know how to test an ABS sensor is to trace the orange plug near the wheel-well (all abs will be orange), unplug it and use a OHM meter to see if it has a closed circuit. once you find the lucky sensor pull the wheel and remove the bolts holding it on and replace it.

I hope this helps a bit.